Safety arrangement for a vehicle

ABSTRACT

Safety arrangement comprising a unit to be located beneath a bonnet of a motor vehicle. The unit is adapted to become of increased length in response to a signal from a sensor and may comprise a bellows-sleeve and a gas generator. The unit has a catch arrangement adapted to engage part of the bonnet structure so that part of the bonnet structure is engaged and retained when the length of the unit is increased.

BACKGROUND OF THE INVENTION

1. Field of the Invention

THE PRESENT INVENTION relates to a safety arrangement, and moreparticularly relates to a safety arrangement for a motor vehicle.

2. Description of Related Art

When a motor vehicle, such as a motor car, is involved in an accident inwhich the front part of the vehicle strikes a pedestrian, it is notuncommon for the head of the pedestrian to be brought forcibly intocontact with the hood or bonnet of the vehicle. This may cause the hoodor bonnet to deform, but, in many cases, that deformation is arrested asthe hood or bonnet engages part of the engine block, or other componentwithin the engine compartment, immediately beneath the hood or bonnet.As a consequence, the movement of the head of the pedestrian is suddenlystopped, and the head of the pedestrian is thus subjected to a verysevere deceleration, which is undesirable.

It has been proposed previously to provide one or more inflatableelements located adjacent the rear edge of the hood or bonnet adapted tobe inflated in an accident situation of the type described, so that therear edge of the hood or bonnet is lifted, thus spacing hood or bonnetfrom the engine block, or other components, within the enginecompartment. This enables the head of a pedestrian, if it strikes a hoodor bonnet in an accident of the type under consideration, to bedecelerated gradually, as the hood or bonnet deforms.

The inflatable elements that have been previous proposed, have beenconventional air-bags, which suffer from the disadvantage that they donot remain inflated for a period of time long enough to provide anadequate degree of protection for a pedestrian during a typical accidentsituation, and also may accelerate the hood or bonnet to such an extentthat the hood or bonnet moves upwardly to such an extent that thepedestrian is injured.

SUMMARY OF THE INVENTION

The present invention seeks to provide an improved safety arrangement.

According to one aspect of this invention there is provided a safetyarrangement for a vehicle having a hood or bonnet, the safetyarrangement comprising a unit adapted to be located beneath the rearpart of the hood or bonnet, the unit incorporating means to increase thelength of the unit in response to a signal from a sensor, the unitcarrying a catch adapted to engage and retain part of the bonnetstructure when the length of the unit is increased.

According to another aspect of this invention there is provided a safetyarrangement in a vehicle having a hood or bonnet, the safety arrangementcomprising a unit located beneath the rear part of the hood or bonnet,the unit incorporation means to increase the length of the unit inresponse to a signal from a sensor, the unit carrying a catch adapted toengage and retain part of the bonnet structure when the length of theunit is increased.

Preferably the unit is provided with a boss provided with twodiametrically opposed spring clips which constitute the catch.

Conveniently the boss is provided with a conical or tapering uppersurface, each spring clip being provided with a free arm defining aninclined portion which is co-aligned with the conical surface, the lowerend of which terminates with a radially inwardly directed arm.

Advantageously the unit incorporates a base, the base carrying apyrotechnic charge, the unit further incorporating an upper platecarrying the boss, there being means connecting the base and the upperplate adapted to increase in length on actuation of the gas generator.

Conveniently part of the unit, when the length thereof has beenincreased, is capable of plastic deformation.

In one embodiment the means between the base and the upper platecomprise a sleeve formed of a plastically deformable material.

Preferably the sleeve is provided with corrugations.

In another embodiment the means between the base and the top platecomprise a piston and cylinder arrangement.

Preferably the piston incorporates a piston rod of plasticallydeformable material and means are provided to retain the piston in anextended position.

Conveniently the unit is provided with means which enable the unit to beconnected to part of the vehicle with a screwing action.

Preferably the unit is provided with a quarter turn screw or abayonet-type connection to secure the unit to part of the vehiclebeneath the hood or bonnet.

Advantageously the bonnet structure is provided with an aperture toreceive said catch, the aperture having a first dimension in onedirection, and a second larger dimension in another direction so thatafter the catch has engaged an edge of the aperture, a quarter turn willrelease the catch.

In an alternative embodiment the unit incorporates an air-bag, theair-bag carrying the catch adapted to engage and retain part of thebonnet structure.

Preferably the air-bag incorporates a sleeve formed from a material thatdoes not permit substantial radial expansion of the sleeve.

Conveniently the sleeve is formed of fabric.

Preferably the sleeve is provided with an inner lining of substantiallygas-tight material.

Conveniently the upper part of the sleeve is trapped in a substantiallygas-tight manner between two inter-engaging elements, one of theinter-engaging elements carrying said catch.

Preferably the catch comprises a catch plate adapted to engage andretain a barb that forms part of the bonnet structure.

Preferably the lower end of the sleeve is received within a grooveformed in a base block.

In a preferred embodiment the air-bag is of cylindrical form, butalternatively the air-bag may be conical with a broad base and a narrowtop carrying the catch.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be more readily understood, and so thatfurther features thereof may be appreciated, the invention will now bedescribed by way of example with reference to the accompanying drawingsin which:

FIG. 1 is a side view of part of a safety arrangement in accordance withthe invention mounted on a motor vehicle,

FIG. 2 is a diagrammatic sectional view of part of the safetyarrangement of FIG. 1,

FIG. 3 is a sectional view taken on the line A—A of FIG. 2,

FIG. 4 is a sectional view taken on the line B—B of FIG. 2,

FIG. 5 is a view corresponding to FIG. 2, showing the arrangement inFIG. 1 following an accident,

FIG. 6 is a view corresponding to FIG. 2, illustrating an alternativeembodiment of the invention,

FIG. 7 is a diagrammatic sectional view of an alternative embodiment ofthe invention, prior to deployment of the safety arrangement, and

FIG. 8 is a view corresponding to FIG. 7 illustrating the arrangement ofFIG. 7 after deployment.

DETAILED DESCRIPTION OF THE INVENTION

Referring initially to FIGS. 1 to 4 of the accompanying drawings, thesafety arrangement in accordance with the present invention isillustrated.

Part of the inner wing structure 1 is provided with a recess ordepression 2, that recession or depression 2 having an aperture 3 formedin the base thereof. Aperture 3 is of circular form provided with tworadially inwardly directed diametrically opposed lugs 4, 5, which haveinclined lower surfaces 6, 7, to form part of a quarter-turn screw or“bayone”-type fixing.

Located above the inner wing structure is the hood or bonnet 8 which isprovided, on its lower surface, with a stiffening structure orreinforcing beam 9. An aperture or cut-out 10 is provided in thestiffening structure 9 at a position above the aperture 3. The cut-out10 is of a cruciform shape having a first pair of opposed arms 11, 12and, orthogonally arranged to the first pair of arms a second pair ofslightly longer opposed arms 13, 14.

A unit incorporating an inflatable element 15 is provided. Theinflatable element is mounted on a base 16. The outer part of the base16 is provided with two helical projections 17, 18 which arediametrically opposed and which are adapted to engage with theprojections 4, 5 of the aperture 3 to form a quarter-turn screw fixingor a bayonet fixing. The base 16 may thus be connected to ordisconnected from the aperture 3 in the inner wing structure with astraightforward screwing action.

The base 16 is provided with a central aperture 18 that receives apyrotechnic inflator or gas generator 19. The base 16 is sealinglyconnected to one end of a sleeve 20 formed of a plastically deformablematerial, such as metal in the form of steel, so that gas from the gasgenerator may be injected into the sleeve 20. The sleeve 20 is providedwith a plurality of corrugations 21. The corrugations may be provided bypressure forming the sleeve in an appropriate die or, alternatively, byprocessing the sleeve using co-operating rollers upon the interior andexterior of the sleeve as the sleeve rotates. The upper end of thesleeve is sealingly connected to an upper plate 22. The upper plate 22carries an upwardly directed boss 23, which has a conical or taperingupper surface 24. The boss is provided with two diametrically opposedspring clips 25, 26. Each spring clip is provided with a free arm 27, 28defining an inclined portion 29, 30, which is co-aligned with saidconical surface, the lower end of which terminates with a radiallyinwardly directed arm 31, 32. The arms 31, 32 are spaced above the uppersurface of the upper plate 22. The spring clips 25, 26 are co-alignedwith the shorter arms 11, 12 of the crucifix-shaped engagement cut-out10.

The upper plate 22 is secured to a bonnet latch release arm 33 which, ascan be seen from FIGS. 1 and 5, extends to a bonnet catch 34. The bonnetcatch 34 may be the ordinarily provided bonnet catch if the bonnet is abonnet of the type that is provided with hinges or other pivotalmounting means at the front of the bonnet, but if the bonnet is of thetype which is provided with rear hinges, the bonnet catch is adapted toretain the hinges in position. In any event, it is to be understood thatwhen the bonnet catch 34 is released, the rear edge of the hood orbonnet 8 is free to move upwardly.

A sensor 35 is provided which may be mounted on the front bumper of themotor vehicle, adapted to sense an impact with a pedestrian. The sensor35 is connected to the gas generator or inflator 19.

When the sensor 35 senses an impact with a pedestrian, and passes asignal to the inflator, the inflator 19 is actuated and gas from theinflator 19 passes into the interior of the sleeve 20. The sleeveexpands, with the upper plate 22 moving upwardly. Thus the length of thesleeve 20 is increased. As the upper plate 22 moves upwardly, the boss23 is directed through the cut-out 10 by the conical surface 24, and theinclined parts 29 and 30 of the free arms 27, 28 and spring slips 25,26, engage against the ends of the relatively short arms 11, 12 of thecruciform-shaped cut-out 10, thus flexing inwardly. As the spring clips25, 26 pass completely through the engagement cut-out 10, the resilientarms 25 and 26 flex back to their initial position with the horizontal,inwardly directed portions 31, 32 engaging the metal in the bonnetstiffening structure 9 to either side of the engagement cut-out 10beyond the ends of the relatively shortly arms 11, 12 of the cruciform.Thus parts of the bonnet stiffening structure are trapped between thespring clips 25, 26 and the upper plate 22.

As the upper plate 22 moves upwardly, the bonnet reaction release arm 33is moved, thus releasing the bonnet catch 34.

As the sleeve 20 continues to expand, the rear part of the bonnet 8 ismoved upwardly, as shown in FIG. 5. Thus, should the head of apedestrian strike the bonnet, the risk of the movement of the head beingarrested, on deformation of the bonnet, due to the impact of the bonnetwith the engine block or other component located within the enginecompartment, is minimised. Also, as the head of a pedestrian strikes thehood or bonnet, a downward force will be applied to the extended sleeve20, causing the extended sleeve 20 to be re-compressed with a plasticdeformation, thus absorbing energy.

One or more vents may be provided, such as the flap 36 which may beadapted to be opened when subjected to a predetermined pressure of gas,to vent the gas from the interior of the expanded sleeve.

The engagement of the spring clips 25, 26 with the bonnet stiffeningstructure serves to hold the rear edge of the bonnet in place andprevents the bonnet tipping forwardly in an undesired manner.

Following deployment of the safety device, the rear edge of the bonnetwill remain in a lifted condition. If it is desired to return the hoodor bonnet to its initial condition, the sleeve 20 may be graspedmanually and may be rotated by 90°, thus disengaging the lower half-turnscrew or bayonet fixing, and also moving the spring clips 25, 26 intoalignment with the longer arms 13, 14 of the cruciform-shaped opening10, thus enabling the unit to be disconnected from both the inner wingstructure and the bonnet stiffening structure.

Whilst the invention has been described above with reference to anembodiment in which an inflatable element is used which has a side wallformed of a plastically deformable material, FIG. 6 illustrates analternative embodiment of the invention in which a unit is providedwherein the base plate 16 carries a cylinder 40 adapted to receive gasfrom the pyrotechnic inflator. A piston 41 is contained within thecylinder adapted to move in response to the supply of gas from theinflator to increase the length of the unit, and the piston 41 isprovided with a piston rod 42 which supports the upper cover. The pistonrod 42 is provided with a ratchet arrangement 43 so that, once thepiston has moved to an extended position, the piston cannot return tothe initial position. The piston rod 42 may be formed of a plasticallydeformable material.

It is to be appreciated that in use of the embodiment shown in FIG. 6,on actuation of the inflator 19, the piston 41 will move from an initialretracted position to an extended position, and will be retained in theextended position by the operation of the ratchet 43. The bonnet willthus, as in the embodiment described above, be lifted. Should the headof the pedestrian strike the bonnet, applying a down-force to thebonnet, the piston rod 41 may deform plastically, thus absorbing energy.

It is to be appreciated that a safety device of the type described abovemay easily be mounted on the vehicle, when the vehicle is on theproduction line, and even if there is a slight mis-alignment, the devicewill still operate in the intended manner, as the conical head 24 willalways “self-align” with the engagement cut-out 10. Because thedescribed unit does not form a constant connection between the bonnetand the inner wing structure, the bellows or the piston will not besubjected to any forces liable to cause metal fatigue. The installationmay be compact and unobtrusive, and thus is unlikely to be damagedduring vehicle servicing.

FIGS. 7 and 8 illustrate an alternative embodiment of the invention.Referring to FIGS. 7 and 8 the described embodiment comprises a basehousing 50, which may be formed as a casting of an appropriatelightweight metal such as aluminium or a tin and lead alloy, such asthat sold under the Trade Mark MAZAC, or even a moulded plasticsmaterial. The base 50 is formed as a monolithic block 51, the block 51having protruding apertured lugs 52, 53, by means of which the block maybe secured in position. The monolithic block defines a cavity 54 whichopens into one side face of the block, the cavity 54 containing a gasgenerator 55. The cavity 54 is connected, by means of a gas flow duct 56formed within the monolithic block 51 to the base of a recess 57 whichis formed at the upper surface of the block. The recess 57 is surroundedby a channel 58. The channel 58 is initially provided with twoupstanding lips, the lips being formed of swageable or malleablematerial so that lips may be deformed inwardly towards each other.

As shown in FIGS. 7 and 8, an inflatable element 60 is provided, havinga bead 59 surrounding an open mouth of the inflatable element. The bead59 is received within the channel 58, and the lips of the channel areswaged or deformed inwardly so as to retain the bead 59 within thechannel surrounding the recess 57.

The inflatable element 60 is formed from a cylindrical inner air-bag 61which is relatively gas-tight, and an outer tubular sleeve 62, which maybe made of fabric, for example, which does not permit any substantialradial expansion. The inflatable element 60 is thus a cylindricalair-bag, but in other embodiments a conical air-bag may be used.

The upper end of the inner air bag 61 and the sleeve 62 is trappedbetween a lower metal cup 63, which has a base 64, and an upwardly andoutwardly directed side wall 65 which terminates with a rolled-over lip66 presenting a curved upper surface, and an upper cup 67 which isnestingly received within the lower cup 63, the upper cup 67 having abase 68 and an upwardly and outwardly directed side wall 69. The uppercup and the lower cup are secured together by means of a rivet 70 whichpasses through co-aligned apertures formed in the centres of the bases64 and 68 of the two cups. Thus, the upwardly and outwardly inclinedside walls 65 and 69 trap between them the inner substantially gas-tightair-bag material 61 and the outer sleeve 62 in a substantially gas-tightmanner.

The dimension of the lower cup 64 is such that at least part of the cupmay be snugly received within the recess 57 formed in the upper surfaceof the monolithic block 51.

Provided within the upper cup 67 is a clip plate 71. The clip plate 71extends across the open mouth of the upper cup 67 and defines a centralaperture 72.

The base block 50 is adapted to be mounted at a position beneath thebonnet or hood on a motor vehicle. FIG. 7 illustrates the under-surface80 of the bonnet or hood which is located above the base block 50. Thebonnet or hood 80 carries a support plate 81 by means of two mountingbrackets 82, 83. The support plate 81 supports a downwardly directlybarb 84. The barb may be formed of a plastics material for example. Thebarb has a pointed lower end 85 and outwardly directed retaining tangs86. The pointed end is located above and substantially in alignment withthe aperture 72 in the catch plate 71.

In an initial condition of the safety arrangement, as shown in FIG. 7,the lower cup 63 is at least partially received within the recess 57,and the bonnet or hood 80 is spaced only a short distance above the baseblock 50. In the event that an impact with a pedestrian is sensed, thegas generator 55 is activated, and gas is injected into the chamber 54,with the gas flowing through the gas flow conduit 56 to the base of therecess 57. The gas serves to inflate the inflatable element 60. Thelength of the unit incorporating the inflatable element 60 thusincreases. The rounded rolled over lips 66 prevent damage occurring tothe inflatable element. The metal cups 63 and 67 move upwardly, and theaperture 72 in the catch plate 71, engages with the pointed lower end 85of the barb 84. The catch plate moves upwardly, initially compressingthe barbs 86 which pass through the aperture 72, and which then expandoutwardly beneath the aperture, so that the barb 84 is securelyconnected to the catch plate 71.

As the cups 63 and 67 move upwardly, an upwardly force is applied to thehood or bonnet 80, causing the hood or bonnet 80 to lift.

The sleeve 62 is formed from a material or fabric that does not allowany substantial radial expansion. Thus the sleeve 62 effectivelyconstrains the air-bag 60 to inflate only in the axial direction, andserves to prevent any lateral movement of the inflated air-bag. It isthought that a simple air-bag, without any inherent strength, might beunstable, allowing the bonnet to move in a direction other than theintended upwardly direction.

It is to be appreciated that when the clip plate of the upper cup hasengaged the barb, when the inflatable element 60 is fully inflated, theengagement of the barb 84, with the clip plate 72, will prevent thebonnet moving further in the upward direction. Thus the describedarrangement moves the hood or bonnet 80 upwardly by a predeterminedamount. Any tendency for the bonnet 80 to move upwardly by a furtheramount will cause the barbs 86 to spread out and to engage the clipplate 71 more securely.

If a pedestrian should hit the bonnet while the bonnet is in theelevated condition, the pedestrian will apply, to the bonnet, a forcetending to press the bonnet down. This will serve to compress theair-bag 61 raising pressure within the inflatable element 60. This risein pressure may cause leakage of gas from the air-bag 61, with that gasflowing through the outer sleeve 62. This leakage of gas will allow thebonnet 80 to move downwardly while absorbing energy, and thusdecelerating the pedestrian in a gradual and desired manner. The impactof the pedestrian with the bonnet will thus be damped.

In the present Specification “comprise” means “includes or consists of”and “comprising” means “including or consisting of”.

1. A safety arrangement for a vehicle having a hood or bonnet, thesafety arrangement comprising a unit adapted to be located beneath therear part of the hood or bonnet, the unit incorporating an inflatableelement to increase the length of the unit in response to a signal froma sensor, the unit carrying a catch adapted to engage and retain part ofthe bonnet structure when the length of the unit is increased.
 2. Asafety arrangement according to claim 1 wherein the unit is providedwith a boss provided with two diametrically opposed spring clips whichconstitute the catch.
 3. A safety arrangement according to claim 2wherein the boss is provided with a conical or tapering upper surface,each spring clip being provided with a free arm defining an inclinedportion which is co-aligned with the conical surface, a lower end ofwhich terminates with a radially inwardly directed arm.
 4. A safetyarrangement according to claim 2 wherein the unit incorporates a base,the base carrying a pyrotechnic charge, the unit further incorporatingan upper plate carrying the boss, there being means connecting the baseand the upper plate, the means connecting the base and upper plateadapted to increase in length on actuation of a gas generator.
 5. Anarrangement according to claim 4 wherein the means between the base andthe upper plate comprise a sleeve formed of a plastically deformablematerial.
 6. An arrangement according to claim 5 wherein the sleeve isprovided with corrugations.
 7. An arrangement according to claim 4wherein the means between the base and the upper plate comprise a pistonand cylinder arrangement.
 8. An arrangement according to claim 7 whereinthe piston incorporates a piston rod of plastically deformable material,and means are provided to retain the piston in an extended position. 9.An arrangement according to claim 1 wherein part of the unit, when thelength thereof has been increased, is capable of plastic deformation.10. An arrangement according to claim 1 wherein the unit is providedwith means which enable the unit to be connected to part of the vehiclewith a screwing action.
 11. An arrangement according to claim 10 whereinthe unit is provided with a quarter turn screw or a bayonet connectionto secure the unit to part of the vehicle beneath the hood or bonnet.12. An arrangement according to claim 10 wherein the bonnet structure isprovided with an aperture to receive said catch, the aperture having afirst dimension in one direction and a second larger dimension inanother direction, so that after the catch has engaged an edge of theaperture, a quarter turn will release the catch.
 13. A safetyarrangement according to claim 1 wherein the unit incorporates anair-bag, the air-bag carrying the catch adapted to engage and retainpart of the bonnet structure.
 14. An arrangement according to claim 13wherein the air-bag incorporates a sleeve formed from a material thatdoes not permit substantial radial expansion of the sleeve.
 15. Anarrangement according to claim 14 wherein the sleeve is formed offabric.
 16. An arrangement according to claim 14 wherein the sleeve isprovided with an inner lining of substantially gas-tight material. 17.An arrangement according to claim 14 wherein an upper part of the sleeveis trapped in a substantially gas-tight manner between twointer-engaging elements, one of the inter-engaging elements carryingsaid catch.
 18. An arrangement according to claim 14 wherein a lower endof the sleeve is received within a groove formed in a base block.
 19. Anarrangement according to claim 13 wherein the catch comprises a catchplate adapted to engage and retain a barb that forms part of the bonnetstructure.
 20. An arrangement according to claim 13 wherein the air-bagis of cylindrical form.
 21. A safety arrangement in a vehicle having ahood or bonnet, the safety arrangement comprising a unit located beneaththe rear part of the hood or bonnet, the unit incorporating aninflatable element to increase the length of the unit in response to asignal from a sensor, the unit carrying a catch adapted to engage andretain part of the bonnet structure when the length of the unit isincreased.
 22. A safety arrangement for a vehicle having a hood orbonnet, the safety arrangement comprising: a gas generator; and a unitmountable beneath a rear part of the hood or bonnet, the unitincorporating an inflatable element, the gas generator capable ofincreasing a length of the unit in response to a signal from a sensor,the unit carrying a catch that can retainably engage part of the bonnetwhen the length of the unit is increased.
 23. A safety arrangementaccording to claim 22, wherein the unit is provided with a boss havingtwo diametrically opposed spring clips which constitute the catch.
 24. Asafety arrangement according to claim 23, wherein the unit includes abase and an upper plate, and a sleeve of plastically deformable materialconnecting the base and the upper plate, the sleeve increasing in lengthupon actuation of the gas generator.
 25. A safety arrangement accordingto claim 23, wherein the unit includes a base and an upper plate, and apiston and cylinder arrangement connecting the base and the upper plate,the piston movable to an extended position upon actuation of the gasgenerator.
 26. A safety arrangement according to claim 25, wherein thepiston and cylinder arrangement include a piston rod of plasticallydeformable material and a ratchet arrangement to retain the piston inthe extended position.
 27. A safety arrangement according to claim 22,wherein the unit is provided with a quarter turn screw connection toenable the unit to be connected to part of the vehicle with a screwingaction.
 28. A safety arrangement according to claim 22, wherein the unitis provided with a bayonet connection to enable the unit to be connectedto part of the vehicle.
 29. A safety arrangement according to claim 22,wherein the unit incorporates an air-bag, the air-bag carrying the catchthat can retainably engage a part of the bonnet.
 30. A safetyarrangement according to claim 29, wherein the air-bag incorporates asleeve formed from a material that does not permit substantial radialexpansion of the sleeve.